Utility of a rapid lamellar body count in the assessment of fetal maturity.

The authors investigated the use of a recently described method for the rapid determination of the lamellar body count (LBC) as a means of evaluating fetal pulmonary maturity. Results of the rapid LBC were compared, alone and in combination with the foam stability index (FSI), with the results obtained by thin-layer chromatography (TLC). The study used 90 consecutive amniotic fluid specimens from 82 patients. Rank ordering of the data suggested cutoff points of 19,000/microL for the rapid LBC and 46 for the FSI. Statistical analysis indicated that the addition of the LBC improved the sensitivity of the FSI (P less than 0.01 by the McNemar test), although the reverse was not the case (P greater than 0.1). The linearity and reproducibility of the LBC were considered acceptable.

Creatine kinase MM isoforms in serum after cardiac surgery.

We evaluated creatine kinase (CK; EC 2.7.3.2) MM3:MM1 isoform ratios in the serum of cardiac patients immediately after cardiac surgery for the diagnosis of perioperative myocardial injury. The mean ratio was 4.8 (range, 1.4-10.7) in 22 patients who had postoperative myocardial complications and 4.6 (1.3-9.6) in 66 patients who did not. By the first postoperative day the ratio had decreased substantially in both groups of patients. The isoform ratio did not correlate with the concentration of total CK, CK-MB, total lactate dehydrogenase (LD), or the incidence of LD1:LD2 or LD5:LD2 ratio reversal. Of these measurements, CK-MB and LD concentrations differed most between the groups of patients; parallel testing of CK-MB and LD showed an optimized sensitivity and specificity of 77% and 87%, respectively. We conclude that analysis for CK-MM isoforms does not add information in the period immediately after cardiac surgery; concentrations of CK-MB and LD correlate with myocardial injury, but the sensitivity and specificity of these measurements may not be high enough for clinical utility.